Driving assistance devices

Abstract

To determine whether or not an object behind a vehicle is a ghost object of the object in front of the vehicle to reduce the possibility of false alarms.SOLUTION: A driving support device includes a rear remote sensing sensor and a forward sensor, and alerts a driver when an object detected by the rear remote sensing sensor meets the predetermined alert conditions. The driving support device does not provide a warning when the alarm conditions are met if all of the following conditions are met: a first condition that the forward sensor detects a forward object, a second condition that a reflective object is detected behind the vehicle, a third condition that the magnitude of the difference between the magnitude of the speed of a target object and the magnitude of the speed of the forward object is equal to or less than a predetermined speed threshold, and a fourth condition that the magnitude of the difference between the distance between the target object and the reflective object and the distance between the forward object and the reflective object is equal to or less than the predetermined distance threshold.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a driving assistance device that issues a warning to alert the driver of a vehicle to an object located behind the vehicle. [Background technology]

[0002] Conventionally, there have been known driving assistance devices that issue a warning to alert the driver to an object located behind the vehicle. For example, a driving assistance device described in Patent Document 1 (hereinafter referred to as the "conventional device") detects a first object approaching from either the left or right rear of the vehicle, and then detects a second object approaching from the other side, and does not issue a warning about the second object if any one of the following first to third conditions is met:

[0003] First condition: The difference in distance between the first object and the vehicle and the second object and the vehicle is equal to or less than a predetermined distance. Second condition: The difference in speed between the first object and the second object is less than a predetermined speed. Third condition: The time difference between the estimated intersection time (required time for closest approach) between the first object and the vehicle and the estimated intersection time between the second object and the vehicle is less than a predetermined time.

[0004] If any of the above conditions 1 to 3 is met, the second object is likely to be a ghost object of the first object, and for this reason, conventional devices do not issue an alarm regarding the second object.

[0005] The conventional device detects objects using millimeter-wave radar. The ghost object is an object that does not actually exist but is mistakenly detected as a result of millimeter waves (reflected waves) being reflected by an object and then further reflected by structures or the like around the vehicle. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2021-112983 Summary of the Invention

[0007] When detecting two objects behind a vehicle, conventional systems determine whether one object is a ghost of the other. However, they cannot determine whether the object behind the vehicle is a ghost of the object in front of the vehicle. As a result, conventional systems may mistakenly detect an object behind the vehicle that does not actually exist and issue an alert when it is not necessary. Such mistaken alerts may be annoying to the driver.

[0008] The present invention has been made to address the above-mentioned problems, and an object of the present invention is to provide a driving assistance device that can reduce the possibility of issuing a false alarm by determining whether an object behind a vehicle is a ghost object of an object in front of the vehicle.

[0009] The driving assistance device of the present invention (hereinafter referred to as "the device of the present invention") rear remote sensing sensors (22L, 22R) configured to transmit a wireless medium to the rear of the vehicle and detect an object located behind the vehicle by reflection of the wireless medium; forward sensors (24L, 24R, 24C, 28A to 28D, 29) configured to detect a forward object (FRO) located in front of the vehicle; a control unit (20) configured to issue a warning (step 630) to alert the driver of the vehicle to the target object that satisfies the warning condition when the object detected by the rear remote sensing sensor satisfies a predetermined warning condition (step 615 "Yes", step 620 "Yes", step 655 "Yes", step 660 "Yes", step 715 "Yes", step 720 "Yes"); Equipped with The control unit When the warning condition is met, A first condition is that the forward sensor detects the forward object (step 625); A second condition is that a reflecting object is detected behind the vehicle, which is located ahead of the target object and which may further reflect the wireless medium reflected by the forward object (step 635). A third condition (step 645) is that the magnitude of the difference between the magnitude of the velocity of the target object and the magnitude of the velocity of the preceding object is equal to or less than a predetermined velocity threshold; and A fourth condition (step 650) is that the magnitude of the difference between the distance between the target object and the reflecting object and the distance between the forward object and the reflecting object is equal to or less than a predetermined distance threshold value. If any of the above conditions is met, the warning is not issued. If any of the first to fourth conditions is not met, the warning is issued (step 630). It is structured as follows.

[0010] According to the device of the present invention, if all of the first to fourth conditions are met, the object behind the vehicle is identified as a ghost object of the object ahead, and no warning is issued even if the warning conditions are met, thereby reducing the possibility of issuing a false warning when the object behind the vehicle does not actually exist.

[0011] In the above description, to facilitate understanding of the invention, the names and / or symbols used in the embodiments described below are enclosed in parentheses for the components of the invention corresponding to those embodiments. However, each component of the invention is not limited to the embodiments defined by the names and / or symbols. Other objects, features, and attendant advantages of the present invention will be easily understood from the following description of the embodiments of the present invention, which will be given with reference to the drawings. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic system configuration diagram of a driving assistance device according to an embodiment of the present invention. [Figure 2]FIG. 2 is an explanatory diagram of the installation positions and detection ranges of the radars shown in FIG. [Figure 3] FIG. 3 is an explanatory diagram of the left blind spot area and the right blind spot area. [Figure 4] FIG. 4 is an explanatory diagram of the left contact area and the right contact area. [Figure 5] FIG. 5 is an explanatory diagram illustrating an outline of the operation of the driving assistance device according to the embodiment of the present invention. [Figure 6] FIG. 6 is a flowchart showing a blind spot warning routine executed by the CPU of the driving assistance ECU shown in FIG. [Figure 7] FIG. 7 is a flowchart showing a contact warning routine executed by the CPU of the driving assistance ECU shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0013] A driving assistance device 10 according to one embodiment of the present invention (hereinafter referred to as "the driving assistance device") is mounted on a vehicle VA. As shown in FIG. 1, the driving assistance device 10 includes a driving assistance ECU (hereinafter referred to as "DSECU") 20.

[0014] ECU is an abbreviation for Electronic Control Unit, and is an electronic control circuit whose main components are a microcomputer including a CPU, ROM, RAM, and interface (I / F). The ECU is also called a "control unit," "controller," or "computer." The CPU performs various functions by executing instructions (routines) stored in memory (ROM). The functions of the DSECU 20 may be performed by multiple ECUs.

[0015] The assistance device 10 includes a plurality of wheel speed sensors 21, a left rear side radar 22L, a right rear side radar 22R, a left front side radar 24L, a right front side radar 24R, and a center front radar 24C. These are connected to the DSECU 20 so as to be able to exchange data.

[0016] The wheel speed sensor 21 is provided for each wheel of the vehicle VA, and generates one pulse signal each time the corresponding wheel rotates a predetermined angle. The DSECU 20 measures the number of pulses per unit time of the pulse signal generated by each wheel speed sensor 21, and obtains the rotational speed (wheel speed) of each wheel based on the measured number of pulses. The DSECU 20 obtains a vehicle speed Vs indicating the speed of the vehicle VA based on the rotational speed of each wheel. As an example, the average value of the rotational speeds of the four wheels is obtained as the vehicle speed Vs.

[0017] As shown in FIG. 2, the left rear-side radar 22L is disposed on the left side behind the vehicle VA. The left rear-side radar 22L emits millimeter waves that propagate within a detection range DR1 (see FIG. 2) on the left rear side of the vehicle VA and receives reflected waves. The reflected waves are millimeter waves that are emitted and reflected by an object located within the detection range DR1. The left rear-side radar 22L acquires the distance D to the object, the lateral position L of the object, and the relative speed Vr of the object based on the emitted and received millimeter waves. The left rear-side radar 22L then transmits radar object information including the distance D, lateral position L, and relative speed Vr to the DSECU 20.

[0018] The detection range DR1 has a predetermined angle θa to the left and right from the "central axis C1 extending from the left rear side radar 22L to the left rear of the vehicle VA," and is the range from the left rear side radar 22L to the maximum detection distance (i.e., the reachable distance of millimeter waves).

[0019] As shown in Fig. 2, the right rear-side radar 22R is disposed on the right side behind the vehicle VA. The right rear-side radar 22R emits millimeter waves that propagate within a detection range DR2 (see Fig. 2) to the right rear of the vehicle VA and receives the reflected waves. The right rear-side radar 22R acquires the distance D, lateral position L, and relative speed Vr based on the emitted and received millimeter waves, and transmits radar object information including these to the DSECU 20.

[0020] The detection range DR2 has a predetermined angle θa to the left and right from the "center axis C1 extending from the right rear-side radar 22R to the right rear of the vehicle VA" and is the range from the right rear-side radar 22R to the maximum detection distance.

[0021] The left front side radar 24L, the right front side radar 24R, and the central front radar 24C are disposed on the left and right sides in front of the vehicle VA, and in the center of the front end of the vehicle, respectively, as shown in Fig. 2. The left front side radar 24L, the right front side radar 24R, and the central front radar 24C emit millimeter waves that propagate to a detection range (not shown) in front of the left side of the vehicle VA, a detection range (not shown) in front of the right side of the vehicle VA, and a detection range (not shown) in front of the center of the vehicle VA, respectively, and receive the reflected waves. The left front side radar 24L, the right front side radar 24R, and the central front radar 24C acquire a distance D, a lateral position L, and a relative velocity Vr based on the emitted and received millimeter waves, and transmit radar object information including these to the DSECU 20. When there is no need to distinguish between the left front side radar 24L, the right front side radar 24R, and the central forward radar 24C, they will be referred to as the "forward radar 24."

[0022] Furthermore, the assistance device 10 includes a rear camera 26, clearance sonars 28A to 28D, and a front camera 29. These are connected to the DSECU 20 so as to be able to exchange data. These will be described in detail in a modified example described later.

[0023] Furthermore, the assistance device 10 includes door mirror indicators 30L and 30R, a buzzer 40, and a display 50. These are connected to the DSECU 20 so as to be able to exchange data.

[0024] The door mirror indicator 30L is provided on the left door mirror LSM and is an indicator for drawing the driver's attention to objects to the left rear of the vehicle VA (see FIG. 2). The door mirror indicator 30R is provided on the right door mirror RSM and is an indicator for drawing the driver's attention to objects to the right rear of the vehicle VA (see FIG. 2).

[0025] The buzzer 40 emits a buzzer sound (warning sound) to draw the driver's attention to an object to the left or right rear of the vehicle VA.

[0026] The display 50 is disposed in a position facing the driver seated in the driver's seat, and displays an indicator to draw the driver's attention to an object to the left or right rear of the vehicle VA.

[0027] <Blind spot alarm> 3, a left blind spot area LDA is defined to the left rear of the vehicle VA, and a right blind spot area RDA is defined to the right rear of the vehicle VA. When the vehicle speed Vs is equal to or greater than a threshold vehicle speed Vsth, the DSECU 20 issues a warning if a blind spot warning condition, which will be described later, is met in at least one of the left blind spot area LDA and the right blind spot area RDA.

[0028] Specifically, the DSECU 20 displays (turns on) the door mirror indicator 30L when the blind spot warning condition is met only in the left blind spot area LDA, and displays (turns on) the door mirror indicator 30R when the warning condition is met only in the right blind spot area RDA. Note that the DSECU 20 displays (turns on) both the door mirror indicators 30L and 30R when the blind spot warning condition is met in both the left blind spot area LDA and the right blind spot area RDA.

[0029] When an object is detected in the first blind spot area DA1, the DSECU 20 determines that the blind spot warning condition is satisfied when the relative speed Vr of the object with respect to the vehicle VA is 0 km / h or greater. The relative speed Vr takes a positive value when the object is approaching the vehicle VA, and a negative value when the object is moving away from the vehicle VA.

[0030] When an object is detected in the second blind spot area DA2, the DSECU 20 determines that the blind spot warning condition is satisfied when the closest approach time Tc, which is the time it takes for the object to come closest to the vehicle VA, is equal to or shorter than a predetermined first threshold time Tcth1. The closest approach time Tc is obtained by dividing the distance D by the relative speed Vr.

[0031] The first blind spot area DA1 is an area a distance d1 in front of the rear end RE of the vehicle VA and an area a distance d2 behind the rear end RE. The second blind spot area DA2 is an area from the rear end RE of the vehicle, ranging from a distance d2 to a distance d3. The first blind spot area DA1 and the second blind spot area DA2 are areas having a width w1.

[0032] For example, the distances d1 to d3 and the width w1 are set to the following values. d1:1m d2:3m d3:60m w1:3m

[0033] This warning can prevent the driver from changing lanes or making other actions when an object that satisfies the blind spot warning conditions is present in the blind spot area.

[0034] <Exit warning> 4, a left contact area LCA is set on the left rear side of the vehicle VA, and a right contact area RCA is set on the right rear side of the vehicle VA. When the vehicle VA is stopped (i.e., when the vehicle speed Vs is 0 km / h), if a contact warning condition described below is met in at least one of the left contact area LCA and the right contact area RCA, the DSECU 20 issues a warning.

[0035] The DSECU 20 displays the door mirror indicator 30L when the contact alarm condition is satisfied only in the left contact area LCA, and displays the door mirror indicator 30R when the contact alarm condition is satisfied only in the right contact area RCA. The DSECU 20 displays the door mirror indicators 30L and 30R when the contact alarm condition is satisfied in both areas LCA and RCA.

[0036] When the contact warning condition is met, the DSECU 20 may not only display the door mirror indicators 30L and / or 30R but also prohibit the door on the side where the contact warning condition is met from being opened.

[0037] The DSECU 20 determines that the contact warning condition is met when the closest approach time Tc of the object detected in the left contact area LCA or the right contact area RCA is equal to or shorter than the second threshold time Tcth2.

[0038] The left contact area LCA and the right contact area RCA are areas at a distance d4 rearward from the front door of the vehicle. The left contact area LCA and the right contact area RCA are areas having a width w2.

[0039] For example, the distance d4 and the width w2 are set to the following values: d4:45m w2:1m

[0040] This warning can reduce the possibility that an object that satisfies the contact warning condition will come into contact with the door or occupant of the vehicle VA when disembarking, if the object is present in the contact area.

[0041] (Overview of operation) An outline of the operation of the assist device 10 will be described with reference to FIG. For example, the millimeter waves emitted by the left rear-side radar 22L are reflected at a reflection point RP of a reflecting object RFO behind the vehicle VA. The millimeter waves reflected at the reflection point RP are reflected by the front object (bicycle) FRP and enter the left rear-side radar 22L via the reflection point RP. In such a case, the left rear-side radar 22L detects the rear object RRO even though the rear object RRO does not exist. The rear object RRO detected in this way is a ghost object of the front object (bicycle) FRO.

[0042] If it is assumed that the rear object RRO, which is a ghost object, satisfies the blind spot warning condition (or the contact warning condition), a warning will be issued even though the rear object RRO does not exist.

[0043] Therefore, even if the rear object RRO satisfies the blind spot warning condition (or the contact warning condition), if all of the following first to fourth conditions are met (i.e., if the ghost condition is met), the support device 10 determines that the rear object RRO is a ghost object and does not issue a warning. First condition: An object (forward object FRO) located in front of the vehicle VA is detected. Second condition: An object (reflecting object) RFO located behind the vehicle VA and in front of the detected rear object RRO is detected. Third condition: The magnitude of the difference ΔV between the magnitude of the velocity Vf of the forward object FRO and the magnitude of the velocity of the rearward object RRO is equal to or less than a predetermined threshold value Vrth. Fourth condition: The magnitude of the difference ΔD between the distance Df between the forward object FRO and the reflecting object RFO and the distance Dr between the backward object RRO and the reflecting object RFO is equal to or less than a predetermined threshold value Dth.

[0044] If the rear object RRO is a ghost object of the front object FRO, the front object FRO and the rear object are likely to move at the same speed, and the distances Df and Dr are likely to be the same. For this reason, the ghost condition is not met unless the third and fourth conditions are met.

[0045] In this embodiment, the relative velocity Vrf of the forward object FRO with respect to the vehicle VA and the relative velocity Vrr of the rearward object RRO with respect to the vehicle VA are used as the velocity Vf and the velocity Vr. The relative velocity Vrf is detected by one of the forward radars 24. The relative velocity Vrr is a value obtained by subtracting the relative velocity Vra of the reflecting object RFO with respect to the vehicle VA from the sensor value detected by one of the left rear-side radar 22L and the right rear-side radar 22R. This is because the sensor value reflects not only the relative velocity Vrr of the rearward object RRO but also the relative velocity Vra. The relative velocity Vra is detected by one of the left rear-side radar 22L and the right rear-side radar 22R.

[0046] It should be noted that the absolute velocity of the forward object FRO and the absolute velocity of the rearward object RRO may be used as the velocity Vf and the velocity Vr, instead of the relative velocity.

[0047] The distance Df is the "distance from the reflecting object RFO to the forward object FRO", and the distance Dr is the "distance from the reflecting object RFO to the backward object RRO".

[0048] The process of acquiring the distance Df and the distance Dr will be described below. First, the assistance device 10 identifies the position of the forward object FRO relative to the vehicle VA based on the distance Df′ and lateral position L included in the radar object information from the forward radar 24. The assistance device 10 identifies the positions of the rear object RRO and the reflecting object RFO relative to the vehicle VA based on the distance D and lateral position L included in the radar object information from the left rear-side radar 22L or the right rear-side radar 22R.

[0049] The support device 10 then identifies the intersection of the reflecting object RFO and a line connecting the rear object RRO and the rear side radar that detected the rear object RRO as a reflection point RP. In this way, the support device 10 identifies the position of the reflection point RP relative to the vehicle VA. The support device 10 obtains a distance Df based on the position of the reflection point RP and the position of the forward object FRO, and obtains a distance Dr based on the position of the reflection point RP and the position of the rear object RRO.

[0050] Even if the rear object RRO satisfies the blind spot warning condition (or the contact warning condition), the assistance device 10 does not issue a warning if all of the first to fourth conditions are met. This reduces the possibility of issuing a false warning even if the rear object RRO is a ghost object.

[0051] (Specific operation) <Blind Spot Warning Routine> The CPU of the DSECU 20 (hereinafter, unless otherwise specified, refers to the CPU of the DSECU 20) executes a blind spot warning routine shown in the flowchart of FIG. 6 every time a predetermined time period has elapsed.

[0052] Therefore, at a predetermined timing, the CPU starts the process from step 600 in FIG. 6 and proceeds to step 605, where it determines whether the vehicle speed Vs is equal to or greater than the threshold vehicle speed Vsth.

[0053] If the vehicle speed Vs is less than the threshold vehicle speed Vsth, the CPU determines "No" in step 605, proceeds to step 695, and temporarily ends this routine.

[0054] If the vehicle speed Vs is equal to or greater than the threshold vehicle speed Vsth, the CPU determines "Yes" in step 605 and proceeds to step 610. In step 610, the CPU determines whether or not at least one of the left rear-side radar 22L and the right rear-side radar 22R has detected an object (rear object RRO).

[0055] If the rear object RRO is not detected, the CPU determines "No" in step 610, proceeds to step 695, and temporarily ends this routine.

[0056] If the rear object RRO is detected, the CPU determines "Yes" in step 610 and proceeds to step 615. In step 615, the CPU determines whether the rear object RRO is located in the first blind spot area DA1.

[0057] If the rear object RRO is located in the first blind spot area DA1, the CPU determines "Yes" in step 615 and proceeds to step 620. In step 620, the CPU determines whether the relative speed Vrr of the rear object RRO (here, the sensor values detected by the left rear-side radar 22L and the right rear-side radar 22R are used) is equal to or greater than "0 km / h".

[0058] If the relative speed Vrr is less than 0 km / h (i.e., if the rear object RRO is moving away from the vehicle VA), the blind spot warning condition is not met. In this case, the CPU determines "No" in step 620, proceeds to step 695, and temporarily ends this routine.

[0059] If the relative speed Vrr is equal to or greater than 0 km / h (i.e., if the rear object RRO is moving in a direction approaching the vehicle VA or is traveling parallel to the vehicle VA), the blind spot warning condition is met. In this case, the CPU determines "Yes" in step 620 and proceeds to step 625.

[0060] In step 625, the CPU determines whether or not a forward object FRO has been detected. If a forward object FRO has not been detected (i.e., the first condition is not met), the ghost condition is not met. In this case, the CPU determines "No" in step 625 and proceeds to step 630. In step 630, the CPU sends an alarm command to the door mirror indicators 30L and 30R, the buzzer 40, and the display 50.

[0061] When the rear object RRO that satisfies the blind spot warning condition is located in the left blind spot area LDA, the CPU transmits a warning command to the door mirror indicator 30L. When the rear object RRO that satisfies the blind spot warning condition is located in the right blind spot area RDA, the CPU transmits a warning command to the door mirror indicator 30R. After executing step 630, the CPU proceeds to step 695 and temporarily ends this routine.

[0062] If the forward object FRO is detected when the CPU proceeds to step 625 (that is, if the first condition is met), the CPU determines “Yes” in step 625 and proceeds to step 635.

[0063] In step 635, the CPU determines whether or not a reflecting object RFO is detected. If a reflecting object RFO is not detected (i.e., the second condition is not met), the CPU determines "No" in step 635 and proceeds to step 630 to send an alarm command. Thereafter, the CPU proceeds to step 695 and temporarily ends this routine.

[0064] If a reflective object RFO is detected (that is, if the second condition is met), the CPU determines "Yes" in step 635 and executes steps 640 and 645 in this order.

[0065] Step 640: The CPU sets the relative speed Vrr of the rearward object RRO to a value obtained by subtracting the relative speed Vra of the reflecting object RFO from the sensor value Vrr of the relative speed of the rearward object RRO. Step 645: The CPU determines whether the magnitude of the difference ΔVr obtained by subtracting the magnitude of the relative speed Vrf of the forward object from the magnitude of the relative speed Vrr is equal to or less than a predetermined threshold value Vrth.

[0066] If the magnitude of the difference ΔVr is greater than the threshold value Vrth (i.e., if the third condition is not met), the CPU determines "No" in step 645, proceeds to step 630, and transmits an alarm command. Thereafter, the CPU proceeds to step 695 and temporarily ends this routine.

[0067] If the magnitude of the difference ΔVr is equal to or smaller than the threshold value Vrth (i.e., if the above third condition is met), the CPU determines "Yes" in step 645 and proceeds to step 650. In step 650, the CPU determines whether the magnitude of the difference ΔD obtained by subtracting the "distance Df between the forward object FRO and the reflecting object RFO" from the "distance Dr between the backward object RRO and the reflecting object RFO" is equal to or smaller than the threshold value Dth.

[0068] If the magnitude of the difference ΔD is greater than the threshold value Dth (i.e., if the fourth condition is not met), the CPU determines "No" in step 650, proceeds to step 630, and transmits an alarm command. Thereafter, the CPU proceeds to step 695 and temporarily ends this routine.

[0069] If the magnitude of the difference ΔD is equal to or greater than the threshold value Dth (i.e., if the fourth condition is met), the CPU determines "Yes" in step 650, proceeds to step 695, and temporarily ends this routine. As a result, if all of the first to fourth conditions are met, no warning is issued even if the blind spot warning condition is met.

[0070] When the CPU proceeds to step 615 and the rear object RRO is not located in the first blind spot area DA1, the CPU determines "No" in step 615 and proceeds to step 655. In step 655, the CPU determines whether the rear object RRO is located in the second blind spot area DA2.

[0071] If the rear object RRO is not located in the second blind spot area DA2, the CPU determines "No" in step 655, proceeds to step 695, and temporarily ends this routine.

[0072] If the rear object RRO is located in the second blind spot area DA2, the CPU determines "Yes" in step 65 and determines whether the closest approach required time Tc is equal to or less than the first threshold time Tcth1.

[0073] If the closest approach required time Tc is greater than the first threshold time Tcth1, the blind spot warning condition is not met. In this case, the CPU determines "No" in step 660, proceeds to step 695, and temporarily ends this routine.

[0074] If the closest approach required time Tc is equal to or shorter than the first threshold time Tcth1, the blind spot warning condition is met. In this case, the CPU determines "Yes" in step 660 and proceeds to the processing of step 625 and subsequent steps.

[0075] <Exit warning routine> The CPU executes the dismount warning routine shown in the flowchart of Fig. 7 every time a predetermined time elapses. In the flowchart of Fig. 7, the same processes as those shown in Fig. 6 are given the same reference numerals, and their explanations will be omitted.

[0076] Therefore, at a predetermined timing, the CPU starts the process from step 700 in FIG. 7 and proceeds to step 705 to determine whether the vehicle VA is stopped (that is, whether the vehicle speed Vs is "0 km / h").

[0077] If the vehicle VA is not stopped, the CPU determines "No" in step 705, proceeds to step 795, and temporarily ends this routine.

[0078] If the vehicle VA is stopped, the CPU determines "Yes" in step 705 and proceeds to step 710. In step 710, the CPU determines whether or not at least one of the left rear-side radar 22L and the right rear-side radar 22R has detected a rear object RRO.

[0079] If the rear object RRO is not detected, the CPU determines "No" in step 710, proceeds to step 795, and temporarily ends this routine.

[0080] If the rear object RRO is detected, the CPU determines "Yes" in step 710 and proceeds to step 715. In step 715, the CPU determines whether the rear object RRO is located in the left contact area LCA or the right contact area RCA.

[0081] If the rear object RRO is not located in either the left contact area LCA or the right contact area RCA, the CPU determines "No" in step 715, proceeds to step 795, and temporarily ends this routine.

[0082] If the rear object RRO is located in the left contact area LCA or the right contact area RCA, the CPU determines "Yes" in step 715 and proceeds to step 720. In step 720, the CPU determines whether the closest approach required time Tc is equal to or less than the second threshold time Tcth2.

[0083] If the closest approach required time Tc is greater than the second threshold time Tcth2, the contact warning condition is not met. In this case, the CPU determines "No" in step 720, proceeds to step 795, and temporarily ends this routine.

[0084] If the closest approach required time Tc is less than or equal to the second threshold time Tcth2, the contact warning condition is met. In this case, the CPU determines "Yes" in step 720, executes steps 625 to 650 shown in FIG. 7, proceeds to step 795, and temporarily ends this routine. If all of the first to fourth conditions are met, no warning is issued even if the contact warning condition is met, but if at least one of the first to fourth conditions is not met, a warning is issued.

[0085] As described above, even if the rear object RRO satisfies the blind spot warning condition (or the contact warning condition), if all of the first to fourth conditions are met, no warning is issued. This reduces the possibility of issuing a false warning even if the rear object RRO is a ghost object.

[0086] The present invention is not limited to the above-described embodiment, and various modifications of the present invention can be adopted.

[0087] (First Modification) The driving assistance device 10 according to this modification detects a reflecting object RFO based on a rear image captured by the rear camera 26.

[0088] As shown in FIG. 2, the rear camera 26 is disposed near the center of the rear end RE of the vehicle VA in the vehicle width direction. The rear camera 26 captures a rear image by capturing an image of the area behind the vehicle VA. The rear camera 26 then acquires the position of an object located in the rear area based on the rear image, and transmits camera object information including the rear image and "information related to the position" to the DSECU 20. The DSECU 20 acquires the relative speed of the object based on the object position history.

[0089] (Second Modification) The driving assistance device 10 according to this modification detects a reflecting object RFO based on the detection results of the clearance sonars 28A to 28D.

[0090] The clearance sonars 28A to 28D are disposed on the rear end RE (more specifically, the rear bumper) of the vehicle VA. The clearance sonars 28A to 28D transmit ultrasonic waves to an area behind the vehicle VA and detect the position and relative speed of an object based on the reflected ultrasonic waves.

[0091] (Third Modification) The driving assistance device 10 according to this modification detects a forward object FFO based on a forward image captured by the front camera 29.

[0092] As shown in FIG. 2, the front camera 29 is disposed above the front windshield FW of the vehicle VA, near the center in the vehicle width direction. The front camera 29 captures a front image by capturing an image of the area ahead of the vehicle VA, and acquires the position of an object located in the front area based on the front image. The front camera 29 then transmits camera object information including the front image and "information related to the position" to the DSECU 20. The DSECU 20 acquires the relative speed of the object based on the object position history.

[0093] (Fourth Modification) The left rear-side radar 22L, the right rear-side radar 22R, the left front-side radar 24L, the right front-side radar 24R, and the center forward radar 24C may be remote sensing sensors that can detect objects by transmitting a wireless medium other than millimeter waves and receiving reflected wireless media. The left rear-side radar 22L and the right rear-side radar 22R may be referred to as "rear remote sensing sensors." The number and locations of the rear remote sensing sensors and the forward radar 24 are not limited to those shown in FIG. 2.

[0094] (Fifth Modification) The driving assistance device 10 can be mounted on vehicles such as an engine vehicle, a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), a fuel cell electric vehicle (FCEV), and a battery electric vehicle (BEV). [Explanation of symbols]

[0095] 10...driving assistance device, 20...driving assistance ECU, 22L...left rear side radar, 22R...right rear side radar, 24L...left front side radar, 24R...right front side radar, 24C...central front radar, 26...rear camera, 28A to 28D...clearance sonar, 29...front camera, 30L...door mirror indicator, 30R...door mirror indicator.

Claims

[Claim 1] a rear remote sensing sensor configured to transmit a wireless medium to the rear of the vehicle and detect an object located behind the vehicle by reflection of the wireless medium; a forward sensor configured to detect a forward object located in front of the vehicle; a control unit configured to, when an object detected by the rear remote sensing sensor satisfies a predetermined alarm condition, issue an alarm to draw the driver's attention to the target object that satisfies the alarm condition; and Equipped with The control unit When the warning condition is met, a first condition that the forward sensor detects the forward object; a second condition that a reflective object that is located behind the vehicle and forward of the target object and does not satisfy the warning condition is detected; a third condition that the magnitude of the difference between the magnitude of the velocity of the target object and the magnitude of the velocity of the forward object is equal to or less than a predetermined velocity threshold; and a fourth condition that the magnitude of the difference between the distance between the target object and the reflecting object and the distance between the forward object and the reflecting object is equal to or less than a predetermined distance threshold; If any of the above conditions is met, the target object is determined to be a ghost object that has been erroneously detected as a result of the wireless medium transmitted by the rear remote sensing sensor being reflected by the reflecting object, the wireless medium reflected by the reflecting object being further reflected by the front object, and the wireless medium reflected by the front object being further reflected by the reflecting object and made incident on the rear remote sensing sensor, and the alarm is not issued; If any one of the first condition to the fourth condition is not satisfied, the warning is issued. It was configured as follows: Driving assistance device.

Images